The Invention relates to the control of hydraulic fluid spills on to a pit floor, the containment of leaked hydraulic fluid, and the monitoring and recycling of such spilled hydraulic fluid.
Wet product or spills on smooth floors or walking surfaces present both safety and environmental concerns, especially if the liquid on such a floor or surface is oil or other hydraulic fluid. Unfortunately, oil and/or other hydraulic fluid leaks and spills are common occurrences in elevator shafts and often present such environmental and safety issues when they occur.
Governmental agencies including the federal EPA, its state counterparts, and OSHA, regulate how leaks and spills are to be handled. In addition to worker safety, these agencies (especially those that regulate environmental protection) seek to ensure that any leaked or spilled oil or other hydraulic fluid that is spilled or leaked onto an elevator pit floor does not enter a storm drain or other reservoir which will result in contamination of ground water, streams or other bodies of water.
There is currently a need for a better system to address the problems associated with leaks and spills of hydraulic fluids, including oil, in elevator shafts and other environments where such fluids could leak into surrounding areas causing contamination.
FIG. 1 depicts a conventional hydraulic elevator of the type widely used in low rise applications such as hotels, motels, shopping centers, office buildings, and hospitals. In FIG. 1, the elevator shaft is cut vertically in half to reveal the inner workings of the hydraulic operations. An elevator car 10 is disposed in a shaft 12 and guided for vertical movement by rollers 14. The car 10 is supported on a piston 16, the lower end of which is disposed in a hydraulic cylinder 18. A pump 20 selectively pumps hydraulic fluid from a reservoir 22 into the interior 24 of the cylinder 18 to raise the car 10, and vents fluid from the interior 24 back to the reservoir 22 to lower the car. As the hydraulic fluid is either inserted into or withdrawn from the cylinder interior 24, the piston will either be pushed up, to raise the elevator car, or be lowered downward, to lower the car.
The piston 16 moves the car 16 between floors, one of which is shown for simplicity. Each floor has at least one door 26. The car 10 has at least one car door 28, which is selectively opened and closed by a door operator 30. Typically, the mechanism which opens and closes the car door or doors 28 interacts with the floor door or doors 26 to open and close the floor doors 26 simultaneously with the car doors 28. A pair of hallway call buttons 32, enabling a passenger to select a desired direction of movement, i.e., “up” and “down,” are provided at each door 26 so that passengers can call for the car 10 to pick them up. Finally, the elevator includes a pair of buffers 34 located in the elevator pit 36 to stop the car 10 from hitting the pit floor 37 in the event the hydraulic lift mechanism 16, 18, 20 fails.
The piston 16 is located in the center of the cylinder 18 and rubber bushings 40 are located at the top of the cylinder between the inside surface of the cylinder and the outside surface of the piston to form a seal.
A car controller 42 controls the general operation of the elevator car 10. The controller 42 is coupled electronically to the call buttons 32 to receive requests to send the car 10 to the corresponding floor. The controller 42 also monitors floor buttons inside the elevator car 10 in which passengers enter the number of the desired floor. The controller 42 also controls the movement of the car 10 as it travels to the requested floor. Once the controller 42 senses that the car 10 has reached the requested floor, the controller 42 releases the car into the control of the door operator 30 which controls the opening and closing of the door 28 and, when completed, releases the car 10 back into the control of the car controller 42. Finally, if the car is one in a bank of multiple elevators, a group controller may be provided, which determines which elevator in the bank should respond to an elevator car call request.
There can also be signals, such as an arrival light and bell adjacent to the doors to indicate that a car has arrived and its direction of travel. Preferably, the elevator includes known safety equipment such as sensors in the door openings.
As the piston 16 is elevated the rubber bushings 40 remove almost all of the hydraulic fluid; however a very thin layer is left to remain as an operational lubricant. As the piston 16 is lowered the rubber bushing shears off a small portion of the hydraulic fluid. Over time and with continued use this very small portion begins to build up and is left resting on top of the elevator cylinder 18. Eventually this build up increases to such a point where the fluid begins to run down from the top of the elevator cylinder to the elevator pit floor 37.
Depending on the frequency of use of the elevator, the rubber bushings will deteriorate over time and the amount of hydraulic lubricant build up and leaking will increase to a point where oil or other fluids can spill onto the pit floor. This process is rarely monitored and typically not documented, which can result in a slippery pit floor.
Based on our observation of the industry, it appears that the typical manner by which this issue is addressed is through the use of a non-fire rated plastic five gallon bucket to collect the hydraulic fluid that leaks from the elevator shaft. Needless to say, this rudimentary “fix” does not adequately address the safety and environmental concerns presented from leaking and spilling hydraulic fluids. To the contrary, depending on how the fluid collected in those buckets is disposed, this common practice may actually contribute to even greater safety concerns and environmental harm.